p-Channel GaN Transistor Based on p-GaN/AlGaN/GaN on Si

In this letter, we demonstrate a recessed-gate p-channel MISFET using a p-GaN (70 nm)/Al0.2Ga0.8N (15 nm)/GaN heterostructure grown by metalorganic chemical vapor deposition (MOCVD) on a Si substrate. A major benefit of such epi-structure is that it contains both a 2-dimensional electron gas (2-DEG) and a 2-dimensional hole gas (2-DHG), hence making it suitable for the GaN-based complementary circuit implementation. In addition, the 2-DEG at the interface of the AlGaN/GaN heterostructure is depleted due to the p-GaN layer on top giving rise to normally-OFF operation for the n-channel transistors. A contact resistivity of 4.9 x 10(-6)Omega . cm(2) is obtained for the ohmic contact to the hole channel for a p-GaN Mg concentration of 2 x 10(20) cm(-3). Long channel (L-g = 3 mu m and L-sd = 9 mu m) p-type transistors show an ON-OFF current ratio of similar to 10(5) and ON resistance of similar to 2.3 k Omega.mm at V-GS = -11 V.